#! /bin/bash

#获取变量字符串长度
test1="Hello World!";
length=${#test1};
echo ${length};

#识别当前所使用的shell
echo $SHELL;
echo $0;

# #检查是否为超级用户
if [ $UID -ne 0 ]
then
    echo Non root user. Please run as root.
else
    echo Root user
fi